Apparatus for regulating humidity



. S. w. CRAMER AND w. B. HODGE.

APPARATUS FOR REGULATING HUMIDITY.

APPLICATION FILED SEPT- 14, i911.

2 SHEETS-SHEET 2- Patented June 28, 1921.

UNITED STATES PATENT 4 OFFICE...

STUART w. omen m wrLLrm B. Home, or CHARLOTTE, nom'rrv CAROLINL, nssrcnons '10 maze-cams. COMPANY, or rrrcnmme, nnssncnusn'r'rs, a

CORIORATION MASSACHUSETTS.

AJPPABATUS FOR nzseum'rmc' HUMIDITY.

Specification of Letters Patent.

Patented June 28, 1921.

Original application filed. December 26, 1907, Serial No. 408,049. Divided and this application filed September 14, 1911.

To all whom it may concern Be it known that we, STUART W. CRAMER and VVILLIAM B. Hones, citizens of the United States, residing at Charlotte, county of Mecklenburg, and State of North Carolina, have invented the new and useful Improvements in Apparatus for Regulating Humidity, described in the following specification.

' Our invention relates to apparatus for antomatically regulating the degree of moisture in factories or other buildings and in separate compartments thereof. It consists in certain improvements in-the structure and in the mode of operation and adjustment oil such apparatus, hereinafter fully described, the present case being a division of our pending application Serial Number 408,049,

' filed December 26th, 1907.

In the accompanying drawings,

Figure 1 is a side elevation of apparatus embodying the invention, partly in section and partly in diagram;

Fig. 2 is a front elevation of the same, partly in diagram;

Fig. 3 a rear elevation;

Fig. 4 is a top plan; 4 v

Fig. 5 a diagram of a part of "the mechanism by which the moisture in the room is caused to increase or decrease according to the control efiected, and Fig. 6 is a detail in diagram oi the moisture varying mecha nism.

The apparatus comprises wet and dry bulb thermometric elements, each consisting of a receptacle filled to a greater or less extent with therein-expansive fluid, such as alcohol, ether or some other liquid or gas adapted to produce changes of internal vapor pressure on changes of the temperature to which the receptacles are subjected, and a flexible walled part or member upon which the changes of such expansion are made effective and which will therefore operate as a motor member adapted to contribute its motive effeet to the operation of the apparatus. In

the present case, such motor member is a.

so-called Bourdon diaphragm, being a hollow tube bent into spiral form and adapted to flex or expand upon increase of its internal pressure and contract upon decrease thereof. The dry bulb element, marked A, is ,subjected in an ordinary dry state to the tem- Serial No. 649,224.

rack Gr engaged by a tangent screw I also mounted on the post, so that the operation of the set screw in one direction or the other will cause the spiral motor member to turn on its central axis.

The wet bulb element comprises a receptacle B similar to the dry bulb receptacle and independently subjected to the wet bulb temperature of the air by being covered with a saturated wiclring after the manner of or- ,dinary hygrometers, or otherwise kept at the wet bulb temperature of the air in the room, so that the volume of its contained fluid will vary therewith. This rece tacle. is connected by a tube and elastic jomt 11 with a flexible walled motor member B which may be of the same type as the dry bulb motor member,being rotatably mounted in.

- the same way upon. a bracket K and provided with a similar segment rack G and tangent set screw H on the bracket by which this motor member also maybe angularly adjusted on its spiral axis. The bracket K is adjustably carried by an upright standard L and on an adjustment screw C which is journaled therein and accessible from the under side of the base 10 as shown in Fig.

1, so that by the operation of the said screw the bracket K and the parts carried thereon can be raised or lowered on'the standard as desired. The standard L is provided with a slot K en aging an extension of the bracket, to which a set nut 12 is applied, for securing the bracket in its adjusted position.

The moisture varying apparatus, by which the degree of moisture put into the room or compartment is controlled or by which the water supply is varied, comprises a suitable valve mechanism, parts of which are diagrammatically indiceted by P and P in the drawings, for controlling the water pipe line, not shown, an external source of power for operating such valve mechanism, which in the present case is an el ctrical s urce 7 with a suitable circuit, and a controlling device consisting of two mutually cotiperating members adapted to operate by engage-- ment,-one withthe other, these members being in the present case the contact terminals of the said circuit. One of the members of the said controlling device is formed by the contact portion 1 of a pointer or lever arm 1 which is mechanically secured to "the free end of the dry bulb motor member A so as to be turned about the axis thereof as the vapor'pressure generated in the receptacle A changes under changing temperatures. The set-screw I above referred to, is for the purpose of setting this pointer member with reference to a temperature scale S mounted on the top of the standard L, as shown in Fig. 1, so that aside from and in addition to its humidity controlling functions later explained, this pointer member may also serve to indicate the temperature of the room to the attendant in charge, who will thus be enabled to control the room-heating apparatus accordingly. 1

It may be remarked at this point that the temperature indication is a desirable adjunct to the apparatus, inasmuch as the relative humidity of the room air is a function of the room temperature and the latter is desirably kept as nearly constant as possible. The higher such temperature is, the lower the humidity will be.

The other member of the controlling device consists of contact portions 2 and 3 of a similarpointer or lever arm (diagrammatically indicated in the drawing and marked 23), which arm is mechanically fastened at 13 (Fig. 1) to the free end of the wet bulb member B'so as to rotate about the axis thereof-according to the pressure changes in the wet bulb receptacle B, the

.two motors being mounted in opposition to each other so that their respective arms 1.

and 23 will move in substantially parallel and proximate planes and in the same direc-v tion with increasing temperature or vice versa. y

In the present case, employing an external operating source which is electrical, the dry bulb lever arm 1 is connected to the common return line 6 of the source 7, and its contact portion 1 is bent over at a right angle to the arm as indicated, so as to be capable of engaging the wet bulb lever arm 23 which is connected to the other end of the circuit with its two contact portions 2 and 3 disposed on opposite sides of the contact 1. The contact ortions 2 and 3 respectively, form the term nals of the branch circuits 4 and 5 (see diagram, Fig.5) containing the parts P and P of the valve mechanism, so that one or the other of these parts becomes actuated according as whether contact is made with one or the other of the contact portions 2 or 3, it being understood that the said parts P and P, as above stated, are the means whereby the external source of power can be made effective, perhaps at some distance from the thermometric elements, to control the supply of moisture to the room. The construction and operation of such devices is well known in this art and will not require further description, further than to point out that in Fig. 6 a section of the moisture supply pipe is shown at 30, and the moisture valve at 31, with suitable connections 32 with the magnets P and P, whereby the said valve is operated in one direction or the other. The arms of the controlling device are indicated in the drawings in diagram, but it will, of course, be understood that they are intended to be formed of any suitable material having sufficient cross-sectional dimension to adapt them to erform the functions ascribed to them wit reliability and uniformity, and that their engagement, one with the other, brings about the desired change in the amount or rate of moisture supplied. The said members of the controlling device are arranged, as stated, to move in the same direction under like changes in temperature of the two thermpmetric elements and at rates of movement corresponding to the dif' ferent rates of change of the wet and dry bulb temperatures, so that'the above mentioned cooperative engagement of the two members will take place only from the differential expansive effects of the wet and dry bulb motor members, and the valve mechanism of the moisture varying apparatus will thus also be controlled by such differential action, as will be readily understood. The tangent screw H which controls the angular position of the wet bulb motor member B, as above described, is adapted to set the arm bearing the contacts 2, 3 withrespect to the position of the contact 1 and in accordance with the difference in temperature between the wet and dry bulb elements or technically, the wet bulb depression that is desired to be established between the'two, and for this purpose it is provided witha pointer M and a depression scale N, the latter being a part of the adjustable bracket K above "eferred to.

When it is desired to maintain a degree of humidity corresponding to a given constant wet bulb depression, this tan ent screw H is turned until the pointer indicates this depression on the scale N. When the temperature of receptacle B becomes lowered sufficiently by evaporation to correspond with the depression which the pointer attached to tangent screw H indicates, contact will thereby be made between 1 and 2, and the moisture varying mechanism will then be put in operation to increase the moisture in the room. When the differnce in temperatures thereafte becomes less than indicated on the scale, contact will then be made between contact members; 1 and 3, and. the operation of the moisture varying mechanism will then be discontinued, and so on, it being observed that the action just described is the result of the difference in the movements of the two arms whereby one'overtakes and makes contact with the other and that such action is independent of the variation range of the room-temperature, that is to say, of the joint position of the two arms with reference to the temperature. scale S. The adjustment afiorded by the screw C provides for a predetermined variation of the wet bulb depression as set by the depression scale N, this being mainly for the purpose of maintaining a constant relative humidity of any desired percentage, a condition which requires an increasing wet loulb depression tor a rising temperature and a decreasingdepression tor a falling temperature, the increase or decrease being of diderent rates for different percentages'of humidity. By adjusting the screw C the axis or" the arm 23 may be brought into, or above or below alinement with the axis oi? the arm 1. When in alinement, the instrument will be set to maintain a degree of humidity corresponding to a fixed wet bulb depression, which, however, will not be a constant relative humidity. When it is desired to maintain a constant relative humidity, the axis of the arm 23 will be set above alinement with the axis of arm 1 asuiiicient distance to give the necessary rate of change in the wet bulb depression as determined by reference to tables prepared for the purpose. If it is desired that the wet bulb depression decrease as the temperature rises, the axis of arm 23 is lowered below that of the arm 1. in either case it willbe observed that the rate at which the lengths of the two arms or members of the controlling device, that is to say, the respective distances between the contact portions and the pivotal axes thereof. The operation of the screw C in the present case tends to shorten or lengthen the efiective length of the wet bulb arm, and thus controls the ratio of one length to the other, but it will be observed that the change is eflected by the relative movement between the two arms and hence that either or both can be subject to adjustment as desired.

By utilizing liquid-containing thermal elements wherein the motor wall or diaphragm is actuated by changes in vapor pressure, we have achieved a great improvement in this art and desire to claim the same as such. Contrary to assumptions heretofore made-by others, we have ascertained and commercially demonstrated that changes in barometnc condmons do n t ad ersel aiie t the accuracy of such thermal elements when differentially combined, because the baro-- metric efiect on one element is substantially off-set by a corresponding effect on the other and also that certain other irregularities in the individual motion-temperature curve of suchinstr'uments are likewise also suflic-iently compensated, when differentially "combined, to be neutralized in their differential effect and thereby we have secured the advantage of the wide range of motion per degre'e of temperature change that is afforded by such elements without any drawbackarising from their inherent and well-known irregularities. The wide range of movement just referred to affords a considerable extent of differential action or motion which is relatively large enough, as we have found, to otiset and render negligible those errors which in other instriunents'are attributable to the other and the possibility of error due to the change in length or shape of any structural part of the instrument may be disregarded because relatively so slight as compared to the differential movement. These several advantages all make for a greater refinement oi the adjustment of the instrument for operating on different specific depressions or on different rates of variable depressions, since as compared with instruments of the bar type a given change in the depression is accomplished by a relatively greater movement of the adjusting screw, thereby enabling a slight adjustment of said screw to produce extremely minute and very accurate setting of the instrument.

We claim: v

1. Apparatus for automatically regulating humidity'comprising in combination, two thermal elements containingliquid adapted to produce change of internal vapor pressure therein according to temperature change and including flexible walls constituting motor members actuated by; such changes, said elements being independently sub ected to the .wet and dry bulb temperatures of the air, a

ill)

ing to different variable wet bulb depres- 3. Aninstrument for regulating humidity comprising in combination, two thermal elements each containing liquid or gas adapted to produce change of internal pressure therein according to temperature change and 1ncluding flexible motor 'wall -members actuated by such changes, said elements being independently subjected to the wet and dry bulb temperatures of the air, valve mechanism for varying'the proportion of moisture in the air, controlling means between said motor members and mechanism whereby the latter is operated only by the difference of the actions of said motor members and means for adjusting the value of the wet bulb depression of the instrument.

l. In apparatus of the kind described, two thermal elements containing liquid adapted to produce changes in the internal vapor pressure according to temperature change and a two-part humidity controlling device difierentially operated by said members and comprising one part connectedto and operated by one of said thermal elements and the other part connected to and operated by the other element.

5. Apparatus for regulating humidity, comprising two flexible hollow spirals internally subjected to the action of vapor or moisture varying apparatus controlled by the difierential action of said arms.

7. Apparatus for regulating humidity, comprising wet and dry bulb thermal elements, each containing liquid and each provided with a rotary contact member movable into contact with each other by the differential efi'ect of the pressure in said element a power source controlled by the contact 0t said members, and moisture-varying apparatus actuated by said power source.

8 Apparatus for regulating. humidity, comprising two flexible hollow spirals subjected to the action of thermal expansivefluid respectively contained therein under wet and dry bulb temperatures respectively, a moisture-varying apparatus controlled by the differential rotary effects of said spirals under changing pressures, and means for setting the relative angular position of said spirals.

In testimony whereof, we have signed this specification in the lpresence of two'witnesses.

S UART W. CRA-MER. WILLIAM B. HODGE. Witnesses to S. W. Cramer:

H. G. KIMBALL, LoUIs SoHoEMMELL. I Witnesses to Wm. B. Hodge:

R0131. I. DALTON, JOHN C. WATSON. 

